De or het soldeerverbinding?

The correct Dutch article is:

de soldeerverbinding

Rule Words ending in -ing: almost always de. See the rule

How to use soldeerverbinding

the soldeerverbindingde soldeerverbinding
this soldeerverbindingdeze soldeerverbinding
that soldeerverbindingdie soldeerverbinding
our soldeerverbindingonze soldeerverbinding
your soldeerverbindingjouw soldeerverbinding
every soldeerverbindingelke soldeerverbinding
which soldeerverbinding?welke soldeerverbinding?
a big soldeerverbinding / the big soldeerverbindingeen grote soldeerverbinding, de grote soldeerverbinding